“Chuck” creators/executive producers Josh Schwartz and Chris Fedak thrilled fans at Comic Con: International: San Diego 2010 today with the announcement that sci-fi icon Linda Hamilton (the “Terminator” films) will join the series as a recurring guest star in season four, playing the role of Mary Bartowski, the long-missing mother of Chuck (series star Zachary Levi) and Ellie (series star Sarah Lancaster).

“Chuck” fans have long wondered about the circumstances surrounding Chuck and Ellie’s mysterious mother, Mary Bartowski, who disappeared from her children’s lives when they were still young.

Hamilton will appear throughout the season, leading Chuck to discover that her life was shrouded in secrets. She was a spy, a CIA agent … and that’s just the beginning. Who is she today? One thing is certain: She’s not the soccer mom who left her children so many years ago.

Season four of “Chuck” premieres Monday, September 20, at 8 p.m. ET/PT on NBC. In advance of the season premiere, Warner Home Video will release Chuck: The Complete Third Season on Blu-ray™ and DVD on September 7.

Hamilton is perhaps best known — especially to Comic-Con fans — for her award-winning role as Sarah Connor in “Terminator” and “Terminator 2: Judgment Day.” She also received Emmy® and Golden Globe Award nominations for her work in the series “Beauty and the Beast,” and her work in the telefilm “A Mother’s Prayer” won her an additional Golden Globe nomination and a CableACE Award. In addition to her recurring role on “Chuck,” Hamilton will guest star in the upcoming season of “Weeds.”